1. Field of the Invention
This invention relates to a forming mold, more particularly to a forming mold for making ceramics having a pattern, such as an intaglio pattern.
2. Description of the Related Art
FIG. 1 illustrates a conventional forming mold 1 for making ceramics. The forming mold 1 includes an upper mold 11 and a lower mold 12 both made of gypsum. The upper mold 11 includes an upper forming portion 111 having an intaglio patterned face 113, and a passage 112 extending through the upper forming portion 111. The lower mold 12 includes a lower forming portion 121 having a top face cooperating with the intaglio patterned face 113 to confine a forming space 13.
To make a ceramic 10, a ceramic slurry is poured into the forming space 13 via the passage 112 either manually or by using a machine, after which the ceramic slurry is dried by a natural drying process or by a heating process. The formed ceramic 10 has an intaglio pattern 101 on an outer surface thereof.
However, the conventional forming mold 1 has the following drawbacks:
1. Whether the ceramic slurry is dried by a natural drying process or by a heating process, the gypsum will absorb the water content of the ceramic 10, so that during the forming process, the ceramic slurry is formed with bubbles. Some of the bubbles are formed on the intaglio patterned face 113. Hence, the detail in the intaglio pattern 101 on the outer surface of the formed ceramic 10 is adversely affected.
2. Protrusions of the intaglio patterned face 113 are hard and brittle, so that they are easily damaged. Such damage is difficult to repair. The presence of such damage also adversely affects the detail in the intaglio pattern 101 on the outer surface of the ceramic 10.
3. When the amount of the ceramic slurry poured into the forming space 13 is insufficient, additional amounts of the ceramic slurry are poured until a sufficient amount of the ceramic slurry is obtained. This results in complicated production of the ceramic 10.